I have a few thousand entries in my IP blacklist.  Once in a great while I'll block a range or block an IP I shouldn't.  Often I only find out about it when I hear that someone's trying to receive an e-mail or whatnot, and it's not arriving.

It'd be helpful to temporarily suspend blacklisted IP checking for some set period ... a few minutes to an hour at most.  Currently the only way I can do this is to try and rename the json file and restart the mail server ... then wait for the e-mail to come in to figure out the IP address ... then check the blacklist file, remove it, rename it back and restart the mail server again.